Photographic direct-print silver halide emulsions



United States l atent O 3,326,689 PHOTOGRAPHIC DIRECT-PRINT SILVER HALIDE EMULSIONS Delbert D. Fix, Rochester, N.Y., assiguor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Jan. 20, 1964, Ser. No. 338,605

13 Claims. (Cl. 96-107) The present invention relates to photography and more particularly, to light-developable or direct-print photographic silver halide emulsions.

Radiation-sensitive papers adapted for light recording, e.g., oscillographic recording, are known. Typical of such papers are the developing-out and print-out type. The developing-out type, as the name implies, requires that the exposed material be chemically developed, fixed and washed in order to provide a stable visible image on said material. The print-out type of material develops on exposure and requires no development step. The print-out type is generally much slower than the developing-out type and the images are unstable and have a short life.

A third type of radiation-sensitive material especially suitable for light-writing and oscillographic recording comprises a hydrophilic colloid-silver halide emulsion layer which, when exopsed to a high intensity source of electromagnetic radiation, forms a latent image which can then be developed by subsequent general exposure to a second source of radiation of lower intensity. Such direct-writing or direct-print emulsions are faster than print-out emulsions and require no chemical development. However, many of the recording papers of this third type have a slow rate of photodevelopment and the background areas tend to build up to obscure the image on subsequent exposure to light. Also, it is often-times desirable to chemically develop and fix direct-print emulsions for purposes of making archival-quality records. However, many direct-print emulsion addenda, while being useful halogen acceptors that serve to' improve directprint images on photodevelopment, tend to cause high fog and reduce the density difference between image and background on chemical development.

It is an object of this invention to provide a new class of light-developable, direct-print, radiation-sensitive silver halide emulsions.

It is another object of this invention to provide novel halogen acceptors for photographic silver halide emulsions used for preparing direct-print recording products.

It is another object of this invention to provide novel photographic light-developable, direct-print silver halide emulsions that can be chemically developed and fixed before or after photodevelopment to make archival-quality records.

It is another object of this invention to provide new photodevelopable photographic silver halide emulsions that are characterized as having a high density difierential between the initially-exposed and unexposed areas upon photodevelopment.

It is also an object of this invention to provide new photodevelopable photographic silver halide emulsions that have high resistance in the initially-unexposed areas to density increase upon photodevelopment and subse quent exposure to light.

These and other objects of the invention are accomplished by incorporating into light-developable, directprint, radiation-sensitive silver halide emulsions thiosemicarbazone halogen acceptors as described below.

ice

The thiosemicarbazones utilized in the silver halide emulsions of the invention can be represented by the formula,

wherein R and R can each be hydrogen atoms, alkyl radicals or aryl radicals, and R can be an alkyl radical or an aryl radical. The alkyl substituents generally have 1 to 10 carbon atoms and can include such substituents as aryl radicals, hydroxyl radicals, or heterocyclic radicals which generally have at least one nitrogen, oxygen or sulfur atom in the heterocyclic nucleus or ring and are preferably rings having 5 to 6 atoms such as morpholino, oxapentamethylene, pyridyl, thiazolyl, and the like. The aryl substituents are of the phenyl or nap/hthyl series and can include various substituents such as alkyl, sulfonyl, carboxyl, amino, and the like. A particularly useful class of halogen acceptors used in the invention are water-soluble compounds prepared by reacting poly-, hydroxy aldehydes such as manno-se, glucose, galactose, glyceraldehyde and the like with thiosemicarbazide, and which can be represented by the formula,

OH OH 1:

wherein x is an integer of 1 to 4. Typical suitable halogen acceptors that can be utilized in the silver halide emulsions of the invention include:

D-mannose thiosemicarbazone,

D galactose thiosemicarbazone, morpholino-2Ppropane thiosemicarbazone, o-phthalaldehyde monoacid thiosemicarbazone, glyoxal bis (thiosemicarbazone) D,L-glyceraldehyde thiosemicarbazone, o-sulfobenzaldehyde thiosemicarbazone sodium salt, benzaldehyde, (4-phenyl-3-thio)-semica-rbazone,

o-tolylaldehyde thiosemicarbazone,

and the like.

The thiosemicarbazone halogen acceptors of the invention can be prepared by reacting a thiosemicarbazide with an aldehyde or a ketone in accordance with usual practice. Reference is made to Berichte 35, 2049 (1902) and Organic Reagents for Organic Analysis, Hopkins and Williams Research Laboratory, Chem. Pub. Co., Inc.,

New York 94 (1946), for typical methods for preparing,

such thiosemicarbazones.

The concentration of the present thiosemicarbazone halogen acceptors utilized in the emulsions of the invention can be widely varied, amounts in excess of those generally utilized for antifoggant purposes in conventional developing-out emulsions being utilized in the present instance. Generally about .1 to 50 mole percent based on the silver halide in the emulsion of the present thiosemicarbazones is utilized.

A wide variety of direct-print or light-developable photographic silver halide emulsions can be utilized in the invention, such being well known to those skilled in the art. Suitable silver halides include silver chloride, silver bromide, silver bromoiodide, silver chloroiodide, and silver chlorobrornoiodide. For a description of suitable emulsions, reference is made to Davey et al. U.S. Patent 2,592,250, issued Apr. 8, 1952; Glafkides, Photographic Chemistry, vol. 1, pp. 31-2, Fountain Press, London; and McBride application Ser. No. 222,964, filed Sept. 11, 1962, wherein is disclosed the preparation of silver halide emulsions in the presence of thioethers such as 3,6-dithia-1,8-octanediol, 1,10-dithia-4,7,13,16-tetraoxacyclooctadecane, 7,10-diaza-1,l6-dicarboxamido-3,14- dithiahexadecane-6, 1 l-dione, 1,17-di-(N-ethylcarbamyl) 6,12-dithia-9-oxaheptadecane and the like. The present silver halide emulsions generally have an average grain size of about .1 to 10 microns, and more generally about .5 to 1 micron.

The so-called internal image emulsions are particularly useful in the invention, such emulsions comprising silver halide grains having a substantial amount, and preferably a predominant amount, of sensitivity internal to the grain. Typically, such internal image emulsions are those which, when measured according to normal photographic techniques by coating a test portion of the emulsion on a transparent support, exposing to a light intensity scale having a fixed time between 1 10 and 1 second, bleaching minutes in a 0.3% potassium ferricyanide solution at 65 F. and developing for about 5 minutes at 65 F. in Developer B below (an internaltype developer), have a sensitivity, measured at a density of 0.1 above fog, greater than the sensitivity of an identical test portion which has been exposed in the same way and developed for 6 minutes at 68 F. in Developer A below (a surface-type developer).

DEVELOPER A G. N-methyl-p-aminophenol sulfate 0.31 Sodium sulfite, desiccated 39.6 Hydroquinone 6.0 Sodium carbonate, desiccated 18.7 Potassium bromide 0 .86 Citric acid 0.68 Potassium metabisulfite 1.5 Water to make 1 liter.

DEVELOPER B N-methyl-p-aminophenol sulfate 2.0 Sodium sulfite, desiccated 90.0 Hydroquinone 8.0 Sodium carbonate, monohydrate 52.5 Potassium bromide 5.0 Sodium thiosulfate 10.0

Water to make 1 liter.

A Wide variety of hydrophilic, water-permeable organic colloids can be suitably utilized in preparing the silver halide emulsions or dispersions of the invention. Gelatin is preferably utilized although other colloidal material such as colloidal albumin, cellulose derivatives, synthetic resins or the like can be utilized. Suitable molloids that can be used are polyvinyl alcohol or a hydrolyzed polyvinyl aceate as described in Lowe, U.S. Patent 2,286,215, issued June 16, 1942; a far hydrolyzed cellulose ester such as cellulose acetate hydrolyzed to an acetyl content of 19 to 26% as described in U.S. Patent 2,327,808, of Lowe and Clark, issued Aug. 24, 1943; a Water-soluble ethanolamine cellulose acetate as described in Yutzy, U.S. Patent 2,322,085, issued June 15, 1943; a polyacrylamide having a combined acrylamide content of 30 to 60 and a specific viscosity of 0.25 to 1.5 on an imidized polyacrylamide of like acrylamide content and viscosity as described in Lowe, Minsk and Kenyon U.S.

.4 Patent 2,541,474, issued Feb. 13, 1951; zein as described in Lowe U.S. Patent 2,563,791, issued Aug. 7, 1951; a vinyl alcohol polymer containing urethane carboxylic acid groups of the type described in Unruh and Smith, U.S. Patent 2,768,154, issued Oct. 23, 1956; or containing cyano-acetyl groups such as the vinyl alcohol-vinyl cyanoacetate copolymer as described in Unruh, Smith and Priest U.S. Patent 2,808,331, issued Oct. 1, 1957; or a polymeric material which results from polymerizing a protein or a saturated acylated protein with a monomer having a vinyl group described in Illingsworth, Bann and Gates U.S. Patent 2,852,382, issued Sept. 19, 1958.

The subject photodevelopable photographic silver halide emulsions of the invention can contain the addenda generally utilized in such products including gelatin hardeners, gelatin plasticizers, coating aids and the like.

The above-described emulsions of the invention can be coated on a wide variety of supports in accordance with usual practice. Typical supports for photographic elements of the invention include paper, glass, cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethyleneterephthalate film and related films of resinous materials and others.

In forming a photodeveloped image With a typical photographic element having coated thereon an emulsion of the invention, the emulsion on the element is initially exposed to a high intensity light source to form a latent image in the emulsion, and thereafter the resulting latent image is photodeveloped by exposing it to a light source of less intensity than the original exposure. A typical instrument for exposing the emulsion of the invention is an oscillograph of the type described by Heiland in US. Patent 2,580,427, issued Jan. 1, 1952. Typical suitable high intensity light sources are mercury vapor lamps that have high blue and ultraviolet emission, xenon lamps that emit light of wavelengths similar to daylight, and tungsten lamps that have high red emission. The low intensity light source that is utilized to effect the photodevelopment after the high intensity exposure can be conventional fluorescent light, a tungsten light or even ordinary daylight. Generally, the latent image formed in the emulsion in the first instance is not visible and does not become visible until photodevelopment. Heat is desirably utilized during the photodevelopment step. Typically the subject emulsions are heated to a temperature of about C. to 200 C. for about 1 to 30 seconds and photodeveloped after. the initial high intensity exposure.

If desired, photographic elements containing the emulsions of the invention can be developed and fixed in aqueous chemical developing-out and fixing solutions after the initial exposure forming the latent image, or after the above-described photodevelopment. The thiosemicarbazone halogen acceptors described above have particular utility with respect to this feature as silver halide emulsions containing such 'addenda can be chemically developed and fixed to make archival-quality records or images having high silver density differential between initially exposed and unexposed areas, such not characterizing silver halide emulsions containing many known halogen acceptors such as stannous salts, thiose-micarbazide, and others. The subject emulsions can be chemically developed in aqueous alkaline compositions containing silver halide developing agents. Typical silver halide developing agents include such compounds as hydroquinone, N methyl-p-aminophenolsulfate, chlorohydroquinone, 2,4 diaminophenol and 3,4-diaminophenol hydrochloride; 3-pyrazolidones such as 1-phenyl-3-pyrazolidone, 4-methyl-1-phenyl-3-pyrazolidone and Z-phenyl- 4,4-dimethyl-3-pyrazolidone; enediols such as ascorbic acid; catechol; pyr-og-allol; gallic acid; p-phenylene diamines; and the like, as well as mixtures of such developing agents. Fixing of the chemically developed emulsions can be eifected With any of the conventional silver halide solvents, aqueous solutions of alkali metal and ammonium thiosulfates or thiocyanates being commonly utilized. 1

The invention is further illustrated by the following examples of preferred embodiments thereof.

Example 1 -grain emulsion. The emulsion was washed with water to remove water-soluble salts. To separate portions of this emulsion were added various halogen acceptors of the invention, and the emulsions were thereafter coated .on'photographic paper supports at coverages of 250 mg.

of silver per square foot and 560 mg. of gelatin per square foot. Several halogen acceptors of the invention were added to the various coatings at 0.37 mole of compound per mole of silver halide. Each of the coatings also contained 2.1 mole percent of potassium iodide based on the silver halide. Portions of the emulsion containing no halogen acceptor of the invention were also coated in a similar manner for comparative purposes. A sample of each coating was exposed for second through a 0.15 log E neutral density step tablet on an Edgerton, Germeshausen and Grier Mark VI sensitometer. The coatings were thereafter photodeveloped by exposure for 5 minutes to 100 foot-candles of cool-white fluorescent light. The density differences between image and background after the photodevelopment was observed for the various coatings, and which density differences are recorded in Table I below as AD. In Table I below is also recorded the density of the 16th 0.15 log E step of each of the coatings after exposure and photodevelopment.

As can be observed from the data set out in Table I above, the various thiosemicarbazones of the invention are useful halogen acceptors in direct-print emulsions, substantial improvements in the density differences between image and background resulting from the use of such addenda in the emulsion.

The direct-print emulsions of the invention have particular utility as they can also be chemically developed and fixed after exposure to make archival-quality records or images having high silver density differential between initially exposed and unexposed areas. Thiosemicarbazide, a compound which is a useful halogen acceptor and closely related to the halogen acceptors of the invention, cannot be effectively chemically developed, unexposed or D areas tending to also develop out. Thiosemicarbazide and several thiosemicarbazone halogen acceptors of the invention were compared as described in more detail in Example 2 below.

Example 2 Several portions of a light-developable, direct-print, light-sensitive gelatino-silver chlorobromoiodide emulsion of the type described in Example 1 were prepared containing various addenda of the invention as described in Table II below at a level of 0.37 mole of addenda per mole of silver halide and coated on photographic paper supports at coverages of 250 mg. of silver per square foot and 560 mg. of gelatin per square foot. Each of the coatings was thereafter exposed in a sensitometer as described in Example 1. The exposed coatings were then chemically developed and fixed (30 second chemical development at F. and 1.5 minute fixing at 72 F.). The developer utilized had the following formula:

G. N-methyl-p-aminophenylsulfate 3.0 Sodium sulfite (anhydrous) 45.0 Hydroquinone 12.0 Sodium carbonate monohydrate 80.0 Potassium bromide 2.0 Water to make 2 liters.

The fixing bath had the formula:

Sodium thiosulfate g 240.0 Sodium sulfite (anhydrous) g 15.0 Acetic acid, 28% cc 48.0 Boric acid g 7.5 Potassium alum g 15.0 Water to make 1 liter.

The density differences between image and background of the processed coatings were observed and such are recorded in Table H below as AD.

TABLE 11 AD after exposure and Feature addenda: chemical development (1) None (control) 0.68 (2) D-mannose thiosemicarbazone 1.29

(3) Morpholino 2 propane thiosemic-arbazone 0.90

(4) o-Phthalaldehyde monoacid thiosemicarbazone 1.23 (5) Thiosemicarbazide 0.10

As can be observed from the data set out in Table II, the thiosemicarbazone halogen acceptors of the invention can be eflFectively chemically developed after exposure to a high intensity flash in the usual manner. Thus, emulsions utilizing such halogen acceptors can be either light-developed, or chemically developed after exposure. It should be noted that the closely-related thiosemicarbazide (feature addenda No. 5 of Table II) significantly reduced the image density difference between the image and background areas (AD).

Example 3 Additional portions of the light-developable, direct-print, light-sensitive gelatino-silver chlorobromoiodide emulsion described in Example 1, except that the emulsion was unwashed, containing 0.037 mole per mole of silver halide of several typical halogen acceptors of the invention were coated as described in Example 1 on paper supports at coverages of 258 mg. of silver per square foot and 560 mg. of gelatin per square foot. The various coatings were thereafter exposed and chemically developed as described in Example 2 above. Summarized below in Table III are the difference in density between the image and background areas (AD).

TABLE III AD after exposure and Feature addenda: chemical development 1) None (control) O (2) D,L-glyceraldehyde thiosemicarbazone 0.97 (3) D-galactose thiosemicarbazone 1.12 (4) Glyoxal bis(thiosemicarbazone) 0.32

(5) o-Sulfobenzaldehyde thiosemicarbazone sodium salt 0.94

(6) Benzaldehyde, (4-phenyl-3-thio)semicarbazone 1.16

7 Example 4 A gelatino-silver chlorobromide direct-print emulsion (95% bromide, 5% chloride) having high internal sensitivity and low surface sensitivity was prepared by slowly adding silver nitrate to an aqueous gelatin solution containing a stoichiometric excess of potassium chloride and potassium bromide to provide a large-grain emulsion. The emulsion was washed water to remove water-soluble salts. To separate portions of this emulsion were added typical feature addenda of the invention at a level of 3.7 mole percent based on the silver halide, and the emulsions were thereafter coated on photographic paper supports at coverages of 258 mg. of silver per square foot and 560 mg. of gelatin per square foot. Each of the coatings also contained 2.1 mole percent of potassium iodide based on the silver halide. The coatings were exposed to a 100 microsecond flash on an Edgerton, Germeshausen and Grier Mark VI sensitometer containing a xenon light source through .a 0.15 log E neutral density step tablet and thereafter photodeveloped for 5 minutes with a 60 foot-candle, cool-white fluorescent light source. The number of visible 0.15 log E steps obtained for the various coatings is summarized in Table IV. Also, the density difference between image and background after the 5 minute photodevelopment was observed for the various coatings, and which density differences are recorded in Table IV as AD.

Each of the 0.15 log E steps referred to in Table IV is equal to a speed increase of more than 1.4 times or equivalent to /z camera stop.

Example 5 A light-developable, direct-print, light-sensitive, gelatino-silver chlorobromoiodide emulsion of the type described in Example 1 was prepared and panchromatic-ally sensitized with a merocyanine dye of the type described in US. Patent No. 2,282,116. To one portion of the emulsion was added .0024 mole of D-glucose thiosemicarbazone per mole of silver halide, and to another portion of the emulsion was added .0024 mole of the halogen acceptor, imidazolidine-Z-thione, per mole of silver halide. To still another portion of the emulsion was added .0018 mole of D-glucose thiosemicarbazone per mole of silver halide plus .0006 mole of imidazolidine-Z-thione per mole of silver halide. The resulting emulsions were coated as described in Example 1. The respective coatings were thereafter exposed in a sensitometer and photodeveloped as described in Example 1. Also, the respective coatings were exposed in a sensitometer as described in Example 1 and chemically developed and fixed as described in Example 2. Table V below summarizes the differences in densities between the image and background areas, AD, for the various emulsions that were exposed and photodeveloped, as well as those exposed and chemically developed.

TABLE V AD After Ex- AD After Ex- Feature Addenda posure and posure and Photo- Chemical development Development (1) None (Control) ca. 0.15 ea. 0. 68 (2) D-glueose thiosemicarbazone 0.40 1. 32 (3) Imidazolidine-2-thione 0.42 1. 17 (4) D-glueose thiosemicarbazone plus imidazolidine-2-thione 0. 45 1. 32

R R R and R can be hydrogen atoms, alkyl groups and including substituted alkyl radicals, aryl radicals such as those of the naphthyl and phenyl series, nitrogen-containing groups such as amino groups (NH and N CHR wherein R is an alkyl or an aryl group such as those of the naphthyl and phenyl series, acyl groups 0 ll ;Ro

wherein R is an alkyl or an aryl group such as those of the naphthyl and phenyl series; and R and R can together be the necessary atoms to make a heterocyclic nucleus with the thiourea grouping to form such cyclic compounds as an imidazole-thione, an imidazoline-thione, a triazine-thiol, a thiobarbituric acid, a thiouracil or the like cyclic compounds and including such substituents as alkyl groups and aryl groups such as those of the naphthyl and phenyl series. The alkyl substituents in the described thioureas can be widely varied although alkyls having 1 to 18 carbon atoms are more generally used. Typical of such thiourea halogen acceptors include:

1-methyl-2-imidazolethione l-n-butyl- 1,2,5 ,6-tetrahydro-1 ,3 ,5-triazine-4-thiol thiourea 1-methyl-2-imidazolinethione 1,3-dimethyl-2-imidazolinethione Z-imidazolinethione thiosemicarbazide tetramethylthiourea l-isopentyl-Z-thiourea 1- (Z-diethylaminoethyl) -1,2,5,6-tetrahydro-1,3,5-

triazine-4-thiol 1,2-bis (1,2,5,G-tetrahydro-1,3,5-triazine-4-thiol) ethane 1-phenyl-2-thiourea 1,3-diphenyl-2-thiourea 4-thiobarbituric acid 2-thiouracil 1-acetyl-2-thiourea 1, 3 -dibenzyl-2-thiourea 1,1-diphenyl-2-thiourea l-ethyl- 1-( a-naphthyl -2-thiourea 2-imidazolethione 1-phenyl-2-imidazolinethione 4,5 -diphenyl-2-imidazolin ethione 1-(o-methoxyphenyl -2-thiourea wherein: X canbe a sulfur or a selenium atom; R can be an alkyl group, an aryl group such as phenyl or a hydrogen atom; Y can be an oxygen atom, a sulfur atom, a selenium atom,

wherein R can be the same substituents as R", and

' 1km wherein-R can be the same'substituents as R", at least one of the substituents for R" and R being a hydrogen atom or a higher alkyl group preferably having -6 to 12 carbon atoms; n is an integer of to 2; R and R are hydrogen atoms, lower alkyl groups or aryl groups such as phenyl; R canbe an alkyl group or an aryl group such as phenyl; and Z represents the atoms required to form a basic heterocyclic nucleus such as benzothiazole, benzoxazole, oxazole, quinoline, naphthothiazole, naphthoxazole, benzimidazole, benzoselenazole, naphthoselenazole, thiazole, thiazoline, pseudoindole and the like. The Y substituent is preferably to form a thiohydantoin nucleus. The alkyl substituents in the described merocyanine dyes can be widely varied although alkyls having 1 to 18 carbon atoms are more generally used, those alkyls denominated lower alkyls having 1 to 4 carbon atoms and those alkyls denominated higher alkyls having to 18 and preferably 7 to 18 carbon atoms. Typical of such merocyanine dyes include 5- 3 -ethyl-2-benzothiazolinylidene ethylidine] rhodanine 5- 3 -ethyl-2-benzothiazolinylidene ethylidene] -2- thio-2,4-oxazolidinedione 5- (3-ethyl-2-benzothiazolinylidene) ethylidene] -3- he ptyl- 1 -phenyl-2-thiohyd antoin 5-[ l-ethylnaphtho{ 1,2-d}thiazolin-Z-ylidene ethylidene] -3-n-heptyl-l-phenyl-Z-thiohydantoin 5 3 -ethyl-2-benzothiazolinylidene)ethylidene1-2- thiohydantoin 5-[ (3-ethylnaphth{2,1-d}oxazolin-2-y1idene)ethylidene] -3 -n-heptyl-1-phenyl-2-thiohydantoin 5 3-ethyl-2-b enzoxazolinylidene) ethylidene] -4- thiohydantoin 3-ethyl-5-[ (3 -ethyl-2-benzothiazolinylidene) ethylidene] -2-thiohydantoin 5- [di( 3 -ethyl-2-benzothiazolinylidene)isopropylidene1- 1-methyl-2-thiob arbituric acid 5- [di (3 -ethyl-2-benzothiazolinylidene)isopropylidene1- Z-thiobarbituric acid 5- [4-( 3 -ethyl-2-benzothiazolinylidene) -2-butenylidene] 3 -n-heptyl-1-phenyl-2-thiohydantoin 5 3-ethyl-S-phenyl-4-oxazolin-2-ylidene) ethylidene] 3-heptyll -phenyl-2-thiohydantoin 1-methyl-5-[ 1,3 3-trimethyl-2-idolinylidene )ethylidene] -2-thiobarbituric acid 5-( 3-ethyl-2-benzothiazolinylidene) -3-heptyl-1-phenyl- 2-thiohydantoin 5- 3 -ethyl-Z-benzothiazolinylidene) ethylidene] -1- phenyl-2-thiobarbituric acid 5- 3-ethylnaphth{2,l-d}oXazo1in-2-ylidene) isopropylidene] -3-heptylrhodanine l-ethyl-S-[ (1 ethylnaphtho{1,2-d}thiazolin-Z-ylidene) isopropylidene]-2-thiobarbituric acid 57[(l-ethyl-2(1H)-quinolylidene)ethylidene]-3-lauryl- 2-thio-2,4-oxazolidinedione 1-methy1-5-[ (3-methyl-2-thiazolidinylidene) ethylidene] Z-thiobarbituric acid 5- [4-(3-methyl-2-benzoxazolinylidene) -1,3-neopentylene-Z-butenylidene] -2-thiobarbituric acid 5- 3 -ethyl-2-benzoselenazolinylidene ethylidene] -3- heptyl-Z-thiohydantoin 5- 3 -(1,2-dihydropyrrolo 2,1-d benzothiazolyl)methy1- ene] -3 -heptyll-phenyl-Z-thiohydantoin 5- 5,6-dichloro-1,3-diethyl-Z-benzimidazolinylidene) ethylidene]-1-ethyl-2-thiobarbituric acid 5- 3-ethyl 2-benzothiazolinylidene) ethylidene] -3- heptyl-Z-seleno-2,4-thiazo1idinedione 5- (3-ethyl-2-benzothiazolinylidene) ethylidene] -3- heptyl-2-thio-2,4-selenazolidinedione 5 3 -ethyl-2-benzothiazolinylidene) ethylidene] -3 heptyl-rhodanine 5-[ (3 -ethyl-2-benzothiazolinylidene )ethylidene] -3- lauryl-rhodanine 5- 3-ethyl-2-benzoxazolinylidene)ethylidene] -3-decyll-phenyl-Z-thiohydantoin 5 (3-ethyl-2-benzoxazolinylidene) ethylidene] -lheptyl-3-phenyl-2-thiohydantoin 3-heptyl-5-( 1-methylnaphtho{ l,2-d}thiazolin-2- ylidene l-phenyl-Z-thiohydantoin The invention has been described in considerable detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion containing a thiosemicarbazone halogen acceptor having the formula R2 R ('3=N-NH 'i-NHR wherein R and R are each selected from the group consisting of hydrogen atoms, alkyl radicals and aryl radicals, and R is selected from the group consisting of an alkyl radical and an aryl radical.

2. A light-developable, direct-print, radiationsensitive hydrophilic colloid-silver halide emulsion containing a thiosemicarbazone halogen acceptor having the formula wherein x is an integer of 1 to 4.

3. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion containing a thiosemicarbazone halogen acceptor having the formula wherein R is an alkyl radical having 1 to 10 carbon atoms.

4. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion containing a thiosemicarbazone halogen acceptor having the formula wherein R is a phenyl radical.

5. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion containing mannose thiosemicarbazone.

6. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion containing glucose thiosemicarbazone.

7. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion containing galactose thiosemicarbazone.

8. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide .emulsion containing morpholino-Z-propane thiosemicarbazone.

9. A light-developable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion containing pht-haladehyde monoacid thiosemicarbazone.

10. A light-developable, direct-print, radiation-sensitive gelatino-silver halide emulsion having silver halide grains with a predominant amount of said radiation sensitivity internal to said grains and containing about .1 to 50 mole percent based on said silver halide of a halogen acceptor having the formula percent based on said silver halide of a halogen acceptor 2 selected from the group consisting of D-rnan'n'ose thiosemicarbazone,

D-galactose thiosemicarbazone,

morpholino-Z-propane thiosemicarbazone,

o-phthalaldehyde monoacid thiosemicarbazone,

glyox-al bis(thi0semicarbazone),

D,L-glyceraldehyde thiosemicarbazone,

o-sulfobenzaldehyde thiosemicarbazone sodium salt,

and benzaldehyde, (4-phenyl-3-thio-)semicarbazone.

12. The process which comprises exposing the lightdevelopable, direct-print, radiation-sensitive hydrophilic colloid-silver halide emulsion described in claim 1 to a high intensity light source and thereby forming a latent image in said emulsion, and thereafter photodeveloping said exposed emulsion with a second light source of less intensity than the first said light source.

13. The process which comprises exposing the lightdevelopable, direct-print, radiation-sensitive silver halide emulsion described in claim 1 to a high intensity light source and thereby forming a latent image in said emulsion, and thereafter chemically developing said latent image to silver with a silver halide developing agent.

No references cited.

NORMAN G. TORCHIN, Primary Examiner.

J. RAUBITSCHEK, Assistant Examiner. 

1. A LIGHT-SEVELOPABLE, DIRECT-PRINT, RADIATION-SENSITIVE HYDROHPLIC COLLOID-SILVER HALIDE EMULSION CONTAINING A THIOSEMICARBAZONE HALOGEN ACCEPTOR HAVING THE FORMULA
 2. A LIGHT-DEVELOPABLE, DIRECT-PRINT, RADIATION-SENSITIVE HYDROPHILIC COLLOID-SILVER HALIDE EMULSION CONTAINING A THIOSEMICARBAZONE HALOGEN ACCEPTOR HAVING THE FORMULA 